/Engine/Source/Runtime/Datasmith/DatasmithCore/Public/IDatasmithSceneElements.h
Set the path name of the Material that the Decal actor uses It can be either a package path referring to an existing material asset or a material name referring a DecalMaterialElement in the DatasmithScene If this is not a DecalMaterialElement or a material with its material domain as DeferredDecal The DecalActor generated in Unreal at import will use its default material
void SetDecalMaterialPathName ( const TCHAR * )